I'm trying to read data from a spectrophotometer through RS-232. Manufacturer specs on communication: every 80 msec the following sequence generated

1Ssimmmm 0mmmmmmm 0mmmmmmm 0mmmmmme 0eeeeeee

S,s,i - some auxiliary bits; m - mantissa; e - exponent. MSB is to the left. Bit7 is set to 0, except for the first byte, to synchronize receiving. When the machine shows ~0.3534 on its little screen I read from the port (hex) 85 53 12 43 7F, which is, if I'm not mistaken,

10000101 01010011 00010010 01000011 01111111

Removing aux bits I get the following float point words
01011010 01100100 10100001 11111111

No matter how I try to convert this thing I do not get anything even close to 0.3. The format manufacturer describes is not quite IEEE 754 (MSB would be to the right). Can anybody help me to decipher what manufacturer meant?

P.S. It's Knauer K2501 spectrophotometer, I contacted Knauer already, but not sure if they will get back to me.